Resource assignment for single and multiple cluster transmission

ABSTRACT

This invention concerns concepts for signaling resource allocation information to a terminal that indicates to the terminal assigned resources for the terminal. The terminal can receives downlink control information (DCI), which comprises a field for indicating the resource allocation information of the terminal. This resource assignment field within the DCI has a predetermined number of bits. The terminal can determines its assigned resource allocation information from the content of the received DCI, even though the bit size of the resource allocation field in the received DCI is insufficient to represent all allowed resource allocations. According to an embodiment, the received bits that are signaled to the terminal in the DCI represent predetermined bits of the resource allocation information. All remaining one or more bits of the resource allocation information that are not included in the field of the received DCI are set to predetermined value.

BACKGROUND Technical Field

The invention generally relates to the signaling of resource allocationinformation to a terminal of a mobile communication system for assigningresources to the terminal. In particular, the invention relates to thesignaling of resource allocations using downlink control information forsingle-cluster and multi-cluster allocations in 3GPP LTE or 3GPP LTE-A.More specifically, one aspect of the invention provides a concept forsignaling resource allocation information for cases where the number ofavailable bits within the downlink control information is insufficientto represent all possible resource allocations that are supported by thesystem, for example, all allowed combinations of single-cluster ormulti-cluster allocations. In principle, the disclosed invention can beapplied to the signaling of uplink resource allocation information anddownlink resource allocation information, while additional advantagesare achieved with regard to certain configuration of uplink resourceallocations in 3GPP LTE or 3GPP LTE-A.

Description of the Related Art

In mobile communication systems, a base station assigns downlinkresources to a terminal, which the base station can use for downlinktransmissions to said terminal, and/or assigns uplink resources to aterminal, which said terminal can use for uplink transmissions. Thedownlink and/or uplink resource allocation (or assignment) is signaledfrom the base station (or another related network device) to theterminal. The downlink and/or uplink resource allocation information istypically signaled as part of a downlink control information havingmultiple predefined flags and/or predefined fields, one of which being afield dedicated for signaling the resource allocation information.

Typically, the available number of bits that can be used to signal theresource assignment information to the terminals is predetermined by atechnical specification. For example, technical specification definesthe size and format of the downlink control information within which theresource assignment information is transmitted to the terminals.

Likewise, the resource allocations, or the size of the resourceallocations are predetermined by a technical specification. Moreover,assignment of the uplink or downlink resources to the terminals istypically defined and given by a technical specification. For example,the uplink resources can be expressed as resource blocks, meaning thatthe granularity on which a user or terminal can be allocated uplinkresources is the number and the position of the assignable uplinkresource blocks. In this case, the technical specification typicallydefines the allowed combinations of resource blocks that are supportedby the mobile communication system. Since the allowed resourceallocations, the size of the resource allocations or the supportedcombinations of assignable resources are defined or predetermined, thenumber of bits that is required to denote all supported (combinationsof) resource(s) is effectively given.

Therefore, neither the available number of bits that can be used tosignal the resource assignment information nor the required number bitsto denote the supported (combinations of) resource(s) can freely bechosen.

The present invention has recognized that situations can occur, in whichthe number of bits that is available for signaling the resourceassignment information is insufficient to represent all possibleresource assignments that are supported by the communication system.

The general concepts of the invention are described below in regard to3GPP LTE and LTE-A communication systems and particularly for multiplecluster allocations specified in 3GPP LTE(-A). However, it is to beunderstood that the reference to 3GPP LTE and LTE-A is only an exampleaccording to specific embodiments of the invention but the generalconcepts of the invention can be applied to different resourceallocation processes of different communication systems.

The disclosed embodiments of the invention for signaling uplink resourceinformation to a terminal can be applied to the signaling of downlinkresource information without departing from the invention. For example,the downlink resources according to LTE(-A) are assigned by thescheduler as resource blocks (RB) as the smallest possible unit ofresources. The downlink component carrier (or cell) is subdivided in thetime-frequency domain in sub-frames, which are each divided into twodownlink slots for signaling control channel region (PDCCH region) andOFDM symbols. As such, the resource grid as illustrated in FIG. 3 foruplink resources in LTE(-A) has the same structure for downlinkresources. Therefore, the signaling of allocated downlink resources withfewer bits that would be required to express all allowed resource blockallocations that are supported by the communication system can beachieved in the same manner as suggested herein with regard to downlinkresources.

Moreover, the terms “resource assignment” and “resource allocation” areused in this specification to denote both the same technical meaning ofassigning or allocating resources. Both terms are thereforeinterchangeable without any change in content and technical meaning.

Long Term Evolution (LTE)

Third-generation mobile systems (3G) based on WCDMA radio-accesstechnology are deployed on a broad scale all around the world. A firststep in enhancing or evolving this technology entails introducingHigh-Speed Downlink Packet Access (HSDPA) and an enhanced uplink, alsoreferred to as High Speed Uplink Packet Access (HSUPA), giving aradio-access technology that is highly competitive.

In order to be prepared for further increasing user demands and to becompetitive against new radio access technologies 3GPP introduced amobile communication system called Long Term Evolution (LTE). LTE isdesigned to meet the carrier needs for high speed data and mediatransport as well as high capacity voice support to the next decade. Theability to provide high bit rates is a key measure for LTE.

The work item (WI) specification on Long-Term Evolution (LTE) calledEvolved UMTS Terrestrial Radio Access (UTRA) and UMTS Terrestrial RadioAccess Network (UTRAN) is finalized as Release 8 (LTE). The LTE systemrepresents efficient packet-based radio access and radio access networksthat provide full IP-based functionalities with low latency and lowcost. According to LTE, scalable multiple transmission bandwidths arespecified such as 1.4, 3.0, 5.0, 10.0, 15.0, and 20.0 MHz, in order toachieve flexible system deployment using a given spectrum. In thedownlink, Orthogonal Frequency Division Multiplexing (OFDM) based radioaccess was adopted due to its inherent immunity to multipathinterference (MPI) caused by a low symbol rate, the use of a cyclicprefix (CP), and its affinity to different transmission bandwidtharrangements. Single-Carrier Frequency Division Multiple Access(SC-FDMA) based radio access was adopted in the uplink, sinceprovisioning of wide area coverage was prioritized over improvement inthe peak data rate considering the restricted transmission power of theuser equipment (UE). Many key packet radio access techniques areemployed including multiple-input multiple-output (MIMO) channeltransmission techniques, and a highly efficient control signalingstructure is achieved in LTE (for example, Release 8).

LTE Architecture

The overall architecture of a communication system according to LTE(-A)shown in FIG. 1. A more detailed representation of the E-UTRANarchitecture is given in FIG. 2.

The E-UTRAN comprises an eNodeB that provides the E-UTRA user plane(PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towardsthe user equipment (UE). The eNodeB (eNB) hosts the Physical (PHY),Medium Access Control (MAC), Radio Link Control (RLC), and Packet DataControl Protocol (PDCP) layers that include the functionality ofuser-plane header-compression and encryption. It also offers RadioResource Control (RRC) functionality corresponding to the control plane.It performs many functions including radio resource management,admission control, scheduling, enforcement of negotiated uplink Qualityof Service (QoS), cell information broadcast, ciphering/deciphering ofuser and control plane data, and compression/decompression ofdownlink/uplink user plane packet headers. The eNodeBs areinterconnected with each other by means of the X2 interface.

The eNodeBs are further connected by means of the S1 interface to theEPC (Evolved Packet Core). More specifically, eNodeBs are connected tothe MME (Mobility Management Entity) by means of the S1-MME and to theServing Gateway (SGW) by means of the S1-U. The S1 interface supports amany-to-many relation between MMEs/Serving Gateways and eNodeBs. The SGWroutes and forwards user data packets, while also acting as the mobilityanchor for the user plane during inter-eNodeB handovers and as theanchor for mobility between LTE and other 3GPP technologies (terminatingS4 interface and relaying the traffic between 2G/3G systems and PDN GW).For idle state user equipments, the SGW terminates the downlink datapath and triggers paging when downlink data arrives for the userequipment. It manages and stores user equipment contexts, e.g.,parameters of the IP bearer service, network internal routinginformation. It also performs replication of the user traffic in case oflawful interception.

The MME is the key control-node for the LTE access-network. It isresponsible for idle mode user equipment tracking and paging procedureincluding retransmissions. It is involved in the beareractivation/deactivation process and is also responsible for choosing theSGW for a user equipment at the initial attach time and at the time ofintra-LTE handover involving Core Network (CN) node relocation. It isresponsible for authenticating the user (by interacting with the HSS).The Non-Access Stratum (NAS) signaling terminates at the MME and it isalso responsible for generation and allocation of temporary identitiesto user equipments. It checks the authorization of the user equipment tocamp on the service provider's Public Land Mobile Network (PLMN) andenforces user equipment roaming restrictions. The MME is the terminationpoint in the network for ciphering/integrity protection for NASsignaling and handles the security key management. Lawful interceptionof signaling is also supported by the MME. The MME also provides thecontrol plane function for mobility between LTE and 2G/3G accessnetworks with the S3 interface terminating at the MME from the SGSN. TheMME also terminates the S6a interface towards the home HSS for roaminguser equipments.

Component Carrier Structure in LTE

The downlink component carrier of a 3GPP LTE (such as Release 8) issubdivided in the time-frequency domain in so-called sub-frames. In 3GPPLTE each sub-frame is divided into two downlink slots as illustrated inFIG. 3, wherein the first downlink slot comprises the control channelregion (PDCCH region) within the first OFDM symbols. Each sub-frameconsists of a given number of OFDM symbols in the time domain (12 or 14OFDM symbols in 3GPP LTE Release 8), wherein each of OFDM symbol spansover the entire bandwidth of the component carrier. Thus, each OFDMsymbol consists of a number of modulation symbols transmitted onrespective N_(RB) ^(DL)×N_(sc) ^(RB) subcarriers as also shown in FIG.4.

Assuming a multi-carrier communication system, e.g., employing OFDM, asfor example used in 3GPP Long Term Evolution (LTE), the smallest unit ofresources that can be assigned by the scheduler is one “resource block”.A physical resource block is defined as N_(sym) ^(DL) consecutive OFDMsymbols in the time domain and N_(sc) ^(RB) consecutive subcarriers inthe frequency domain as illustrated in FIG. 4. In 3GPP LTE (such asRelease 8), a downlink physical resource block thus consists of N_(symb)^(DL)×N_(sc) ^(RB) resource elements, corresponding to one slot in thetime domain and 180 kHz in the frequency domain. Further details on thedownlink resource grid can be obtained, for example, from 3GPP TS36.211, “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation (Release 8)”, version 8.9.0 or 9.0.0, section6.2, available at http://www.3gpp.org and incorporated herein byreference. Likewise, the sub-frame structure on a downlink componentcarrier and the downlink resource grid illustrated in FIGS. 3 and 4 areobtained from 3GPP TS 36.211.

For the LTE uplink resource allocation, the structure of the resourceblocks is comparable to the above structure of the downlink resourcegrid. For the uplink resources, each OFDM symbol consists of a number ofmodulation symbols transmitted on respective N_(RB) ^(UL)×N_(sc) ^(RB)subcarriers as also shown in FIG. 5. The exemplary structure of anuplink resource grid illustrated in FIG. 5 corresponds to the structureof the exemplary downlink resource grid illustrated in FIG. 4. Theexemplary uplink resource grid of FIG. 4 is obtained from 3GPP TS 36.211V10.0.0, which is incorporated herein by reference and provides furtherdetails of the uplink resources in LTE (Release 10).

L1/L2 Control Signaling—Downlink Control Information in LTE(-A)

In order to inform a scheduled user or terminal about their allocationstatus, transport format and other data related information (e.g., HARQinformation), L1/L2 (Layer1/Layer2) control signaling is transmitted onthe downlink along with the data. L1/L2 control signaling is multiplexedwith the downlink data in a sub-frame, assuming that the user allocationcan change from sub-frame to sub-frame. It should be noted that userallocation might also be performed on a TTI (Transmission Time Interval)basis, where the TTI length is a multiple of the sub-frames. The TTIlength may be fixed in a service area for all users, may be differentfor different users, or may even by dynamic for each user. Generally,the L1/2 control signaling needs only be transmitted once per TTI. TheL1/L2 control signaling is transmitted on the Physical Downlink ControlChannel (PDCCH). It should be noted that in 3GPP LTE, assignments foruplink data transmissions, also referred to as uplink scheduling grantsor uplink resource assignments, are also transmitted on the PDCCH.

Generally, the information sent on the L1/L2 control signaling(particularly LTE(-A) Release 10) can be categorized to the followingitems:

-   -   User identity, indicating the user that is allocated. This is        typically included in the checksum by masking the CRC with the        user identity;    -   Resource allocation information, indicating the resources        (Resource Blocks, RBs) on which a user is allocated. Note, that        the number of RBs on which a user is allocated can be dynamic;    -   Carrier indicator, which is used if a control channel        transmitted on a first carrier assigns resources that concern a        second carrier, i.e., resources on a second carrier or resources        related to a second carrier;    -   Modulation and coding scheme that determines the employed        modulation scheme and coding rate;    -   HARQ information, such as a new data indicator (NDI) and/or a        redundancy version (RV) that is particularly useful in        retransmissions of data packets or parts thereof;    -   Power control commands to adjust the transmit power of the        assigned uplink data or control information transmission;    -   Reference signal information such as the applied cyclic shift        and/or orthogonal cover code index, which are to be employed for        transmission or reception of reference signals related to the        assignment;    -   Uplink or downlink assignment index that is used to identify an        order of assignments, which is particularly useful in TDD        systems;    -   Hopping information, e.g., an indication whether and how to        apply resource hopping in order to increase the frequency        diversity;    -   CQI request, which is used to trigger the transmission of        channel state information in an assigned resource; and    -   Multi-cluster information, which is a flag used to indicate and        control whether the transmission occurs in a single cluster        (contiguous set of RBs) or in multiple clusters (at least two        non-contiguous sets of contiguous RBs). Multi-cluster allocation        has been introduced by 3GPP LTE-(A) Release 10.

It is to be noted that the above listing is non-exhaustive, and not allmentioned information items need to be present in each PDCCHtransmission depending on the DCI format that is used.

DCI occurs in several formats that differ in their overall size and thefield information that is used. The different DCI formats that arecurrently defined for LTE(-A) Release 10 are described in detail in TS36.212 v10.0.0 in section 5.3.3.1, available at http://www.3gpp.org andincorporated herein by reference.

The following two specific DCI formats defined in LTE show exemplarilysome of the functionality of the various DCI formats:

-   -   DCI format 0 is used for the scheduling of the PUSCH (Physical        Uplink Shared Channel) using single-antenna port transmissions        in uplink transmission mode 1 or 2,    -   DCI format 4 is used for the scheduling of the PUSCH (Physical        Uplink Shared Channel) using closed-loop spatial multiplexing        transmissions in uplink transmission mode 2.

Uplink transmission modes 1 and 2 are defined in TS 36.213 v10.0.1 insection 8.0, the single-antenna port is defined in section 8.0.1, andthe closed-loop spatial multiplexing is defined in section 8.0.2, whichare available at http://www.3gpp.org and incorporated herein byreference.

There are several different ways how to exactly transmit the informationpieces mentioned above. Moreover, the L1/L2 control information may alsocontain additional information or may omit some of the information, suchas:

-   -   the HARQ process number may not be needed in case of a        synchronous HARQ protocol, as, for example, used in uplink,    -   Spatial-multiplexing related control information, such as, for        example, precoding, may be additionally included in the control        signaling, or    -   In case of multi-code word spatial multiplexing transmission,        the MCS and/or HARQ information for multiple code words may be        included.

For uplink resource assignments (e.g., concerning the Physical UplinkShared Channel, PUSCH) signaled on PDCCH (Physical Downlink ControlChannel) in LTE, the L1/L2 control information does not contain a HARQprocess number, since a synchronous HARQ protocol is employed for LTEuplink transmissions. The HARQ process to be used for an uplinktransmission is determined and given by the specified timing.Furthermore, it is to be noted that the redundancy version (RV)information and the MCS information are jointly encoded.

Downlink & Uplink Data Transmissions in LTE(-A)

This section provides further background on downlink and uplink datatransmissions according to the technical specification of LTE(-A) thatmay be useful to comprehend the background, framework and full usabilityof the subsequently discussed embodiments of the invention. This sectiontherefore provides only illustrative information concerning backgroundinformation, a person skilled in the field of the invention willconsider as common knowledge.

Regarding downlink data transmission in LTE, L1/L2 control signaling istransmitted on a separate physical channel (PDCCH), along with thedownlink packet data transmission. This L1/L2 control signalingtypically contains information on:

-   -   The physical resource(s) on which the data is transmitted (e.g.,        subcarriers or subcarrier blocks in case of OFDM, codes in case        of CDMA). This information allows the UE (receiver) to identify        the resources on which the data is transmitted.    -   When user equipment is configured to have a Carrier Indication        Field (CIF) in the L1/L2 control signaling this information        identifies the component carrier for which the specific control        signaling information is intended. This enables assignments to        be sent on one component carrier which are intended for another        component carrier (“cross-carrier scheduling”). This other,        cross-scheduled component carrier could be for example a        PDCCH-less component carrier, i.e., the cross-scheduled        component carrier does not carry any L1/L2 control signaling.    -   The Transport Format, which is used for the transmission. This        can be the transport block size of the data (payload size,        information bits size), the MCS (Modulation and Coding Scheme)        level, the Spectral Efficiency, the code rate, etc. This        information (usually together with the resource allocation        (e.g., the number of resource blocks assigned to the user        equipment)) allows the user equipment (receiver) to identify the        information bit size, the modulation scheme and the code rate in        order to start the demodulation, the de-rate-matching and the        decoding process. The modulation scheme may be signaled        explicitly.    -   Hybrid ARQ (HARQ) information:        -   HARQ process number: Allows the user equipment to identify            the hybrid ARQ process on which the data is mapped.        -   Sequence number or new data indicator (NDI): Allows the user            equipment to identify if the transmission is a new packet or            a retransmitted packet. If soft combining is implemented in            the HARQ protocol, the sequence number or new data indicator            together with the HARQ process number enables soft-combining            of the transmissions for a PDU prior to decoding.        -   Redundancy and/or constellation version: Tells the user            equipment, which hybrid ARQ redundancy version is used            (required for de-rate-matching) and/or which modulation            constellation version is used (required for demodulation).        -   UE Identity (UE ID): Tells for which user equipment the            L1/L2 control signaling is intended for. In typical            implementations this information is used to mask the CRC of            the L1/L2 control signaling in order to prevent other user            equipments to read this information.

To enable an uplink packet data transmission in LTE, L1/L2 controlsignaling is transmitted on the downlink (PDCCH) to tell the userequipment about the transmission details. This L1/L2 control signalingtypically contains information on:

-   -   The physical resource(s) on which the user equipment should        transmit the data (e.g., subcarriers or subcarrier blocks in        case of OFDM, codes in case of CDMA).    -   When user equipment is configured to have a Carrier Indication        Field (CIF) in the L1/L2 control signaling this information        identifies the component carrier for which the specific control        signaling information is intended. This enables assignments to        be sent on one component carrier which are intended for another        component carrier. This other, cross-scheduled component carrier        may be for example a PDCCH-less component carrier, i.e., the        cross-scheduled component carrier does not carry any L1/L2        control signaling.    -   L1/L2 control signaling for uplink grants is sent on the DL        component carrier that is linked with the uplink component        carrier or on one of the several DL component carriers, if        several DL component carriers link to the same UL component        carrier.    -   The Transport Format, the user equipment should use for the        transmission. This can be the transport block size of the data        (payload size, information bits size), the MCS (Modulation and        Coding Scheme) level, the Spectral Efficiency, the code rate,        etc. This information (usually together with the resource        allocation (e.g., the number of resource blocks assigned to the        user equipment)) allows the user equipment (transmitter) to pick        the information bit size, the modulation scheme and the code        rate in order to start the modulation, the rate-matching and the        encoding process. In some cases the modulation scheme maybe        signaled explicitly.    -   Hybrid ARQ information:        -   HARQ Process number: Tells the user equipment from which            hybrid ARQ process it should pick the data.        -   Sequence number or new data indicator: Tells the user            equipment to transmit a new packet or to retransmit a            packet. If soft combining is implemented in the HARQ            protocol, the sequence number or new data indicator together            with the HARQ process number enables soft-combining of the            transmissions for a protocol data unit (PDU) prior to            decoding.        -   Redundancy and/or constellation version: Tells the user            equipment, which hybrid ARQ redundancy version to use            (required for rate-matching) and/or which modulation            constellation version to use (required for modulation).    -   UE Identity (UE ID): Tells which user equipment should transmit        data. In typical implementations this information is used to        mask the CRC of the L1/L2 control signaling in order to prevent        other user equipments to read this information.

There are several different available ways of how to exactly transmitthe information pieces mentioned above in uplink and downlink datatransmission in LTE. Moreover, in uplink and downlink, the L1/L2 controlinformation may also contain additional information or may omit some ofthe information. For example:

-   -   HARQ process number may not be needed, i.e., is not signaled, in        case of a synchronous HARQ protocol.    -   A redundancy and/or constellation version may not be needed, and        thus not signaled, if Chase Combining is used (always the same        redundancy and/or constellation version) or if the sequence of        redundancy and/or constellation versions is pre-defined.    -   Power control information may be additionally included in the        control signaling.    -   MIMO related control information, such as, e.g., pre-coding, may        be additionally included in the control signaling.    -   In case of multi-code word MIMO transmission transport format        and/or HARQ information for multiple code words may be included.

For uplink resource assignments (on the Physical Uplink Shared Channel(PUSCH)) signaled on PDCCH in LTE, the L1/L2 control information doesnot contain a HARQ process number, since a synchronous HARQ protocol isemployed for LTE uplink. The HARQ process to be used for an uplinktransmission is given by the timing. Furthermore it should be noted thatthe redundancy version (RV) information is jointly encoded with thetransport format information, i.e., the RV info is embedded in thetransport format (TF) field. The Transport Format (TF) respectivelymodulation and coding scheme (MCS) field has for example a size of 5bits, which corresponds to 32 entries. 3 TF/MCS table entries arereserved for indicating redundancy versions (RVs) 1, 2 or 3. Theremaining MCS table entries are used to signal the MCS level (TBS)implicitly indicating RV0. The size of the CRC field of the PDCCH is 16bits.

For downlink assignments (PDSCH) signaled on PDCCH in LTE the RedundancyVersion (RV) is signaled separately in a two-bit field. Furthermore themodulation order information is jointly encoded with the transportformat information. Similar to the uplink case there is 5 bit MCS fieldsignaled on PDCCH. 3 of the entries are reserved to signal an explicitmodulation order, providing no Transport format (Transport block) info.For the remaining 29 entries modulation order and Transport block sizeinfo are signaled.

Resource Allocation Fields for Uplink Resource Assignments

According to 3GPP TS 36.212 v10.0.0, the DCI formats 0 can, for example,be used for uplink resources assignments. The DCI formats 0contains—amongst others—a so-called “resource block assignment andhopping resource allocation” field, which has a size of ┌log₂ (N_(RB)^(UL)(N_(RB) ^(UL)+1)/2)┐ bits, where N_(RB) ^(UL) denotes the number ofresource blocks in the uplink.

LTE-(A) presently foresees three possible uplink resource allocationschemes, which are single-cluster allocation with non-hopping PUSCH(Physical Uplink Shared channel), single-cluster allocation with hoppingPUSCH and multi-cluster allocation. Multi-cluster allocation isintroduced in Release 10 and is only supported as with non-hoppingPUSCH.

In case of a single-cluster allocation with non-hopping PUSCH, theentire “resource block assignment and hopping resource allocation” fieldof the DCI is used to signal the resource allocation in the uplinksub-frame.

In case of a single-cluster allocation with hopping PUSCH, theN_(UL_hop) MSB (most significant bits) of the field are used to specifythe detailed hopping configuration, while the remainder of the fieldprovides the resource allocation in the first slot in the uplinksub-frame. AT N_(UL_hop) can thereby be determined from the systembandwidth according to table 1. Table 1 is obtained from table 8.4-1 of3GPP TS 36.213 v10.0.1, which is incorporated herein by reference. Thesystem bandwidth N denotes the number of uplink physical resourceblocks.

TABLE 1 Number of Hopping bits System Bandwidth for second slot RAN_(RB) ^(UL) N_(UL) _(—) _(hop) 6-49 1 50-110 2

In case of a multi-cluster allocation with non-hopping PUSCH, the uplinkresource allocation is signaled using the concatenation of the frequencyhopping flag field and the resource block assignment and hoppingresource allocation field of the DCI.

The case of multi-cluster allocation with hopping PUSCH is not definedin LTE. For this reason, the frequency hopping flag field (as requiredfor single-cluster allocation) can be used for signaling uplink resourceallocation in case of multi-cluster allocation.

For multi-cluster allocations,

$\left\lceil {\log_{2}\left( \begin{pmatrix}\left\lceil {{N_{RB}^{UL}/P} + 1} \right\rceil \\4\end{pmatrix} \right)} \right\rceil$

bits are required to denote or specify all allowed and supportedcombinations. According to 3GPP LTE(-A) multi-cluster allocation, thesmallest unit of uplink resources that can be assigned is one “resourceblock group” (RBG) as outlined below in more details.

The size of the RBG can be determined from the system bandwidthaccording to table 2. Table 2 is obtained from table 7.1.6.1-1 of 3GPPTS 36.213 v10.0.1 by replacing N_(RB) ^(DL) with N_(RB) ^(UL)accordingly. The system bandwidth N_(RB) ^(UL) denotes the number ofuplink physical resource blocks.

TABLE 2 System Bandwidth RBG Size N_(RB) ^(UL) (P) ≤10 1 11-26 2 27-63 3 64-110 4

Multi-Cluster Allocation Interpretation

As mentioned above, hopping is not supported for LTE multi-cluster RBA.The hopping flag of the DCI is therefore prepended to the RBA field,which increases the size by 1 bit. While for single-cluster theallocation is based on a resource-block granularity, for multi-clusterallocations the granularity is based on a resource block group (RBG). AnRBG is the union of P adjacent RBs, where P can be established usingTable 2 for any uplink system bandwidth supported by LTE. The onlyexception is the case where N_(RB) ^(UL) is not an integer multiple ofP, and where therefore the last RBG contains the remaining RBs. Each RBis part of only one RBG. The number of uplink RBGs N_(RBG) ^(UL) canthen be computed as

$N_{RBG}^{UL} = {\left\lceil \frac{N_{RB}^{UL}}{P} \right\rceil.}$

As multi-cluster allocation is known and defined in 3GPP LTE Release 10,further details of the RBGs and the allowed combination of RBs (whichform the RBGs) that are supported by the system are not required andtherefore omitted. The multi-cluster allocation according to 3GPP LTERelease 10 and specifically the DCI format 0 for signaling themulti-cluster resource allocation as defined in 3GPP TS 36.212 V10.0.0is incorporated herein by reference.

According to 3GPP LTE Release 10, multi-cluster allocations arerestricted to support only two clusters, where the first cluster isidentified by the starting RBG s₀ and ending RBG s₁−1, and where thesecond cluster is identified by the starting RBG s₂ and ending RBG s₃−1.These four parameters are then linked into a single value r whichrepresents the multi-cluster allocation by the following formula:

${r = {{\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle} + {{\langle\begin{matrix}{N - s_{1}} \\{M - 1}\end{matrix}\rangle}{\langle\begin{matrix}{N - s_{2}} \\{M - 2}\end{matrix}\rangle}} + {\langle\begin{matrix}{N - s_{3}} \\{M - 3}\end{matrix}\rangle}}},$

where m=4 (corresponding the four starting and ending RBGs that define amulti-cluster consisting of two clusters), N=N_(RBG) ^(UL)+1 and1≤s₀<s₁<s₂<s₃≤N, and where

${\langle\begin{matrix}x \\y\end{matrix}\rangle} = \left\{ {\begin{matrix}{\begin{pmatrix}x \\y\end{pmatrix} = \frac{x!}{{y!} \cdot {\left( {x - y} \right)!}}} & {x \geq y} \\0 & {x < y}\end{matrix}.} \right.$

Furthermore, 3GPP LTE Release 10 requires that the two clusters arenon-adjacent, i.e., there is a spacing of at least one RBG between theend of the first cluster and the start of the second cluster. Thisconditions leads to the above formula and the inequality relationsbetween values s₀, s₁, s₂, s₃.

The present invention has recognized that for most cases (i.e., for mostvalues of the uplink system bandwidth define by the specification 3GPPTS 36.213), the number of available bits in the DCI and required bits todenote all allowed RBG allocation combinations supported by the systemare matching. However, for some cases an insufficient number of bits isavailable in the DCI as outlined above.

BRIEF SUMMARY

The invention is intended to overcome one or more of the discussed andoutlined problems of known resource allocation concepts of mobilecommunication systems or to improve the signaling of the known resourceallocation concepts.

It is an object of the invention to provide an improved method forsignaling resource allocation information to a terminal of a mobilecommunication system used for assigning resources to the terminal, aswell as a corresponding terminal and a corresponding base station.

This object is solved by the subject matter of the independent claims.

Preferred embodiments of the invention are defined by the dependentclaims.

The present invention has recognized that situations can occur, in whichthe number of bits available for signaling the resource assignmentinformation is insufficient to represent the allowed resourceassignments that are supported by the communication system. In case ofLTE, the “allowed resource assignments” can be the different RBG (i.e.,the allowed combinations of RBs) resource allocations that are supportedby the system for multi-cluster allocation.

A first embodiment of the invention concerns a method performed by aterminal of a mobile communication system to receive and determineresource allocation information that indicates to the terminal assignedresources for the terminal. The terminal receives, according to thisembodiment, downlink control information (DCI), which comprises a fieldfor indicating a resource allocation for the terminal. This resourceassignment field within the DCI has a predetermined number of bits. Theterminal determines its assigned resource allocation information fromthe content of that field in the received DCI, even though—at least forone or more specific resource allocation cases—the predetermined bitsize of the resource allocation field in the received DCI isinsufficient to represent all allowed resource allocations that aresupported by the communication system. According to this embodiment, itis therefore suggested that the received bits that are signaled to theterminal in the mentioned field of the DCI represent predetermined(subset of) bits of the resource allocation information. All remainingone or more bits of the resource allocation information that are notincluded in the field of the received DCI are set to predeterminedvalue, e.g., to either 1 or 0.

The DCI used to signal the resource allocation information can have apredetermined format, in which case the number of bits of the field thatis used for signaling the resource allocation information in the DCI canbe predefined for any allowed bandwidths supported by the system. Thisimplies that the terminal is able to determine the expected bit size ofthe signaled resource allocation information (i.e., the size of thefield within the received DCI containing the resource allocationinformation).

Another embodiment of the invention concerns a method of transmittingresource allocation information for assigning resources to a terminal ofa mobile communication system. For this, a base station determines theresource allocation information to be transmitted to the terminal. Thebase station can further determine the number of bits that are availablefor signaling the resource allocation information within the downlinkcontrol information (DCI). The number of available bits can thereby bethe size of one or more field(s) for transmitting resource allocationinformation within the DCI. The number of bits that are available forsignaling the resource allocation information (i.e., the bit size of thementioned field within the DCI) is predetermined for a given bandwidth(and can therefore be determined by the base station, and by theterminal as soon as it is aware of the relevant bandwidth).

If the number of available bits for signaling the resource allocationinformation is insufficient to represent the plurality of allowedresource allocations, the base station transmits a predetermined subsetof bits of the resource allocation information within the field of theDCI to said terminal. All remaining one or more bits of the resourceallocation information that are not, or cannot be, transmitted to theterminal have a predetermined value or are set to a predetermined value.

According to a specific embodiment of the invention the mobilecommunication system is a 3GPP LTE system or 3GPP LTE-A system. In thiscase, the terminal is a user equipment (UE) or a relay node. Likewise,the base station is an evolved Node B (eNodeB) or a relay node. The DCIformat in this case can be the DCI format 0 as defined in 3GPP LTE or3GPP LTE-A. Alternatively, DCI format 4 as defined in 3GPP LTE or 3GPPLTE-A may be used for some embodiments of the invention.

The aforementioned remaining one or more bits of the resource allocationinformation that are not signaled in said field of said DCI can be themost significant bit(s), MSBs, or the least significant bit(s), LSBs, ofsaid resource allocation information.

Further, the position and/or the value of these remaining one or morebits within the resource allocation information can either be predefined(e.g., in the system according to a technical requirementsspecification), or predetermined by the base station and then signaledto the terminal.

Further embodiments of the inventions concern 3GPP LTE, where theresource allocation information represents the allocation of resourceblocks, RBs, according to a single-cluster resource allocation in DCIformat 0 or DCI format 4 defined in 3GPP LTE or 3GPP LTE-A.

Alternatively or additionally, the resource allocation information canrepresent the allocation of resource block groups, RBGs, according to amulti-cluster resource allocation in DCI format 0 or DCI format 4defined in 3GPP LTE or 3GPP LTE-A, where an RBG comprises a predefinedplurality of adjacent RBs.

It is further foreseen according to an embodiment of the invention thatthe value and the positions of said remaining one or more bits of theresource allocation information (that are not signaled in the field ofthe DCI) are predetermined in order to limit the number or combinationsof RBs that are assignable to said terminal.

Alternatively, the value and the positions of the remaining one or morebits can be predetermined to limit the number or combinations of RBGsthat are assignable to the terminal.

According to this embodiment of the invention, the predetermined valueand the predetermined positions of the remaining one or more bits can bechosen so as to exclude an allocation of one or more edge physicalresource blocks, PRBs, for example useable by the communication systemfor physical uplink control channel, PUCCH, transmissions. It mayfurther be advantageous to exclude an allocation of one or more edgephysical resource blocks since this reduces the amount of generatedout-of-band interference, i.e., power that is leaked outside of theallowed bandwidth.

Further embodiments of the invention propose a re-interpretation orre-mapping scheme for the signaled resource allocation information thatis applied by the base station and/or the terminal to change the RBs,RBGs or the combinations thereof that are assignable to said terminal.

This re-interpretation scheme can include a mirroring from low RB or RBGindices to high RB or RBG indices, respectively, and vice versa.Alternatively or additionally, the re-interpretation scheme can includea shift of the signaled resource allocation information by apredetermined offset, wherein the offset is defined as a number of RBsor RBGs.

The re-interpretation scheme can be configured by a base station or canbe signaled by said base station to said terminal.

According to a further embodiment of the invention is a method oftransmitting resource allocation information for assigning uplinkresources to a terminal of a 3GPP LTE or 3GPP LTE-A communication systemprovided. The method is performed by a base station or relay node. Thebase station is configured to transmit resource allocation informationwithin a field of downlink control information, DCI, to the terminal.The resource allocation information can thereby represent differentresource block groups, RBGs, according to a multi-cluster resourceallocation in said 3GPP LTE or 3GPP LTE-A communication system. Theavailable bit size of the field of the DCI used for transmitting theresource allocation information is thereby sufficient to represent aplurality of possible uplink resource allocations, because the RBG sizeis determined according to a novel manner.

The RBG size according to this embodiment of the invention can bedetermined for a given number of uplink resource blocks according to:

N_(RB) ^(UL) P_(RBG) ^(UL) ≤6, 8     1  7, 9-26 2 27-54 3 55-84, 91-100 4 85-90, 101-110 5

Alternatively, the RBG size according to this embodiment of theinvention can be determined for a given number of uplink resource blocksaccording to:

N_(RB) ^(UL) P_(RBG) ^(UL) ≤6 1 7-26 2 27-54  3 55-84  4 85-110 5

In both cases, the value N_(RB) ^(UL) denotes the number of uplinkresource blocks and the value P_(RBG) ^(UL) denotes the correspondingRBG size in number of RBs.

According to still a further embodiment of the invention is method ofreceiving resource allocation information for assigning uplink resourcesto a terminal of a 3GPP LTE or 3GPP LTE-A communication system provided.The method is performed by the terminal or relay node. The terminal isconfigured to receive downlink control information, DCI that comprises afield for signaling the resource allocation information of saidterminal. This field has a predetermined number of bits and the resourceallocation information represents resource block groups, RBGs, accordingto a multi-cluster resource allocation in said 3GPP LTE or 3GPP LTE-Acommunication system. The bit size of the field of the DCI used forsignaling the resource allocation information is thereby sufficient torepresent a plurality of possible uplink resource allocations, becausethe RBG size is determined according to a novel manner. The manner ofdetermining the RBG size for a given number of uplink resource blocks isbased on either of the two tables shown above.

According to yet another embodiment of the invention is terminalprovided for receiving resource allocation information for assigningresources to said terminal within a mobile communication system. Theterminal comprises means for receiving downlink control information, DCIthat comprises a field for indicating the resource allocationinformation of the terminal. The field has a predetermined number ofbits. The terminal further comprises means for determining the resourceallocation information from the bits of the field in the received DCI.The predetermined number of bits of the field in the received DCI isthereby insufficient to represent the plurality of allowed resourceallocations that are supported by the communication system, e.g.,insufficient to represent the plurality of allowed multi-clusterresource allocations. Therefore, it is suggested that the bits of thefield in the received DCI represent predetermined bits of the resourceallocation information, while all remaining one or more bits of theresource allocation information that are not included in the field ofthe received DCI are set to predetermined value.

According to a further embodiment of the invention is a base stationprovided for transmitting resource allocation information for assigningresources to a terminal of a mobile communication system. The basestation comprises means for determining resource allocation informationthat is to be transmitted to the terminal. The base station furthercomprises means for determining the number of available bits forsignalling the resource allocation information within downlink controlinformation, DCI. The number of available bits is thereby the size ofthe field for transmitting resource allocation information within saidDCI. Moreover, the DCI has a predetermined format and for a givenbandwidth the number of bits available for signalling the resourceallocation information within the DCI is specified. The base stationfurther comprises means for transmitting a predetermined subset of thebits of the resource allocation information within the field of the DCIto the terminal, if the number of available bits for signalling theresource allocation information is insufficient to represent theplurality of allowed resource allocations, while all remaining one ormore bits of the resource allocation information that are nottransmitted have a predetermined value.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE FIGURES

In the following the embodiments and aspects of the invention aredescribed in more detail under reference to the attached figures.Similar or corresponding details in the figures are marked with the samereference numerals.

FIG. 1 shows an exemplary architecture of a 3GPP LTE system,

FIG. 2 shows an exemplary overview of the overall E-UTRAN architectureof 3GPP LTE,

FIG. 3 shows an exemplary sub-frame structure on a downlink componentcarrier as defined for 3GPP LTE (Release 10),

FIG. 4 shows an exemplary downlink resource grid of a downlink slot asdefined for 3GPP LTE (Release 8/9),

FIG. 5 shows an exemplary uplink resource grid of an uplink slot asdefined for 3GPP LTE (Release 10),

FIG. 6 shows the number bits available within DCI format 0 forspecifying the allocated RBG and the number of required bits to specifyall allowed RBGs as supported and defined by 3GPP LTE (Release 10) inregard to one aspect of the present invention,

FIG. 7 shows an exemplary method for receiving and determining resourceallocation information at a terminal of a mobile communication systemaccording to one aspect of the present invention,

FIG. 7A shows exemplary steps of the determination of the resourceallocation information of the exemplary method of FIG. 7 according toanother embodiment of the present invention, and

FIG. 8 shows an exemplary method for determining and transmittingresource allocation information by a base station of a mobilecommunication system according to one aspect of the present invention.

DETAILED DESCRIPTION

This section will describe various embodiments of the invention. Forexemplary purposes only, most of the embodiments are outlined inrelation to an orthogonal single-carrier uplink radio access schemeaccording to 3GPP LTE (such as Release 8 or 9) and LTE-A (such asRelease 10) mobile communication systems discussed in the TechnicalBackground section above. It is to be noted that the invention may beadvantageously used in connection with a mobile communication systemsuch as 3GPP LTE and LTE-A communication systems previously described,but the invention is not limited to this particular exemplarycommunication system.

The details given herein of 3GPP LTE and LTE-A are intended to provide abetter understanding of the invention and should not be understood aslimiting the invention to the described specific implementation detailsof the described mobile communication system.

As discussed above, the invention has recognized that situations canoccur, in which the number of bits available for signaling the resourceassignment information is insufficient to represent the allowed resourceassignments that are supported by the communication system. In case ofLTE multi-cluster allocation, the allowed resource assignments are thedifferent RBG (i.e., the allowed combinations of RBs) allocationcombinations that are supported by the system.

For the specific case of LTE multi-cluster allocations according to DCIformat 0, the number of bits for the resource allocation field that arerequired to address all allowed RBG combinations is (as explained above)

$\left\lceil {\log_{2}\left( \begin{pmatrix}\left\lceil {{N_{RB}^{UL}/P} + 1} \right\rceil \\4\end{pmatrix} \right)} \right\rceil.$

The bits available in the DCI to signal the uplink resource allocationto the terminal can be computed from ┌log₂(N_(RB) ^(UL)(N_(RB)^(UL)+1)/2)┐+1, where the “+1” is the result of using the “frequencyhopping field flag” as discussed in the background section and asspecified in 3GPP LTE-A Release 10.

For most numeric cases covered by the 3GPP LTE specification formulti-cluster allocation, the number of available bits and required bitsshows no problem. However, in some cases not sufficient bits areavailable, as shown in FIG. 6.

Specifically, FIG. 6 shows the number bits available within DCI format 0for specifying the allocated RBG and the number of required bits tospecify all allowed RBG combinations as supported and defined by 3GPPLTE, Release 10, for multi-cluster allocation.

As can be obtained from FIG. 6 or the above given formulas, the numberof bits available in the DCI format 0 is insufficient for the followingnumber of N_(RB) ^(UL): 7, 9, 10, 55-63, 85-90, 101-110 (where only therange from 6-110 has been regarded exemplarily and for simplicity). Asnoted above, N_(RB) ^(UL) denotes the system bandwidth in terms of thenumber of physical uplink resource blocks.

For the 3GPP LTE-(A) specification, the currently supported systembandwidth for uplink transmissions ranges from 6 to 110, while at leastthe values 5, 15, 25, 50, 75 and 100 are currently commonly used values.Thus, for commonly used system bandwidths the number of available bitsin the DCI is sufficient to represent all allowed resource allocations.

These “allowed” resource allocations are the allocations that aresupported by the technical specifications of LTE(-A). For single-clusterallocation, the allowed resource allocations are the different sets ofuplink resource blocks that are assignable to the UEs and supported bythe LTE(-A) system. More specifically, for single-cluster allocation,the assigned uplink resources are each adjacent uplink resource blocks(RBs). The assigned uplink resources are specified in the DCI by thefirst RB and the length of the uplink resource, i.e., the number RBs.The first RB and length information are combined into a resourceindication value RIV, as provided by TS 36.213 v10.0.1 section 8.1.1,that is to be signaled in the DCI. Additionally, the DCI includes a flagfor indicating whether frequency hopping is used for the allocation.

For multi-cluster allocation, the allowed resource allocations are thedifferent combinations of uplink resource block groups (RBGs) that areassignable to the UEs and supported by the LTE(-A) system. Morespecifically, LTE multi-cluster allocation supports multi-clusterallocation with two clusters, where each cluster is a chunk of adjacentRBGs (and therefore RBs) and where the two clusters are separated by atleast one RBG (as noted above and specified in LTE-A release 10). Thus,the plurality of different allowed resource allocations formulti-cluster allocation can be seen as all different combinations ofRBGs within two clusters that are supported by the LTE-A specification.As noted before, the assigned multi-cluster allocation according to LTERelease 10 is signaled as one value r that is determined based on thebeginning and ending RB of the two clusters according a rule defined inthe LTE-A specification (e.g., TS 36.213 v10.0.1 section 8.1.2). As alsonoted above, the LTE-A specification further defines that the hoppingflag of the DCI used for single-cluster allocation is to be also usedwhen signaling the multi-cluster allocation information r.

For future releases, the allowed number of clusters may be greater thantwo and multi-cluster allocation may be introduced for downlink resourceallocation too. However, the allowed resource allocations, i.e., thedifferent RBs or RBGs, and a manner to signal them to the UEs in DCIwill also be provided by future releases. The number of bits that arerequired to represent all allowed resource allocations is given by andcan unambiguously determined from the technical specification itself.

According to the example of FIG. 6, one or two additional resourceinformation bits would be required (i.e., for bandwidths 7, 9, 10,55-63, 85-90, 101-110) to be able to address all allowed RBGs that aresupported by LTE, i.e., to represent all allowed values of themulti-cluster allocation information r.

Since the number of bits is predefined by the LTE technicalspecification (as outlined above), the UE can determine the size of thesignaled resource allocation information by itself, or the UE can bepre-configured to a given resource allocation information size. In otherwords, the LTE technical specification requires that for a givenbandwidth (e.g., N_(RB) ^(UL)=7 in the example of FIG. 6) the resourceallocation information (e.g., the value r) has a certain bit-size (e.g.,7 in the example of FIG. 6 for N_(RB) ^(UL)=7). Likewise, the LTEspecification defines the DCI format including the size of field forsignaling the resource allocation information to the UE. If this size isinsufficient to represent all allowed values r, the UE expects toreceive resource allocation information with a certain bit size, but theactually received information in the DCI has a smaller bit-size. The UEbehavior for handling such a situation is not specified and therefore isundefined. The UE preferably ignores the whole received information inthis undefined situation to avoid behavior that negatively affects theterminal or system performance.

To resolve the problem of insufficient bits in the DCI to represent allallowed assignable resource allocations (e.g., for bandwidths 7, 9, 10,55-63, 85-90, 101-110 in FIG. 6), the straightforward solution is to addthe additionally required one or more bits to the respective field inthe DCI so that all assignable resource allocations can be expressed andsignaled to the UE.

However, this feasible solution has the drawback that it would not bebackward compatible to earlier LTE releases (e.g., releases 8 and 9),specifically to UEs that are manufactured to conform to those releasesonly. Moreover, it has the disadvantage that the resource allocationinformation signaled to the UE as part of the DCI has different sizes(i.e., different numbers of bits) for single-allocation and for multiplecluster allocation, which adds substantial complexity because anadditional DCI size that needs to be detected increases the blinddecoding efforts required to detect the DCI at the UE.

The invention proposes a different solution to this problem caused byinsufficient available bits in the DCI, including but not limited to LTEmulti-cluster allocations according to DCI format 0. The proposedsolution does not increase the number of bits used in the transmittedDCI for signaling the allocated resources, for example assigned RBGs forLTE multi-cluster allocations according to DCI format 0, and thereforekeeps the DCI detection complexity at the UE at the same level.

According to one embodiment of the invention, only as many bits of theresource allocation information as can be sent in the DCI are signaledto the UE if the number of available bits in the DCI is insufficient.All remaining bits of the resource allocation information (i.e., thosebits for which additional bits would be required as discussed above) areassumed to be, or set to, a predefined value. In other words, theseremaining bits of the resource allocation information (for examplerepresenting the value r discussed above for multi-cluster allocation)that cannot be signaled in the DCI due to insufficient bits are set toeither 0 or 1. The “resource allocation information” in this context isthe information required to represent all allocations (e.g., all RBGsfor multi-cluster allocation) that are supported by the LTEspecification.

Consequently, it is suggested to provide a new interpretation of thesignaled bits at the transmitter (eNodeB) and receiver (UE) sides sothat the known and unchanged DCI format can nonetheless be used tosignal a meaningful resource allocation information.

In the following, this approach for 3GPP LTE multi-cluster allocationusing DCI format 0 is developed. For this, the following mathematicalproperties are used:

$\begin{matrix}{\begin{pmatrix}x \\y\end{pmatrix} = {\begin{pmatrix}{x - 1} \\y\end{pmatrix} + \begin{pmatrix}{x - 1} \\{y - 1}\end{pmatrix}}} & \left( {{Equation}\mspace{14mu} 1} \right)\end{matrix}$

It can be noted that each of these terms is 0 or a positive integernumber for any non-negative integers x and y. As the invention isconcerned with uplink or downlink resource allocations, these conditionsare always fulfilled.

$\begin{pmatrix}x \\y\end{pmatrix} \geq {\begin{pmatrix}x \\{y - 1}\end{pmatrix}\mspace{14mu} y} \leq \left\lceil \frac{x}{2} \right\rceil$$\begin{pmatrix}x \\y\end{pmatrix} \geq \begin{pmatrix}{x - 1} \\y\end{pmatrix}$

To analyze the value r, it is helpful to analyze the relationshipbetween the two first terms

${\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle}\mspace{14mu} {and}\mspace{14mu} {{\langle\begin{matrix}{N - s_{1}} \\{M - 1}\end{matrix}\rangle}.}$

Assuming that N−s₀≥M and N−s₁≥M−1, it is possible to write these termsas

${{\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle}\mspace{14mu} {and}\mspace{14mu} {\langle\begin{matrix}{N - s_{1}} \\{M - 1}\end{matrix}\rangle}},$

respectively.

The first term can be converted according to Equation 1 to:

${\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle} = {\begin{pmatrix}{N - \left( {s_{0} + 1} \right)} \\M\end{pmatrix} + {\begin{pmatrix}{N - \left( {s_{0} + 1} \right)} \\{M - 1}\end{pmatrix}.}}$

Therefore, the following applies:

${\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle} \geq {\begin{pmatrix}{N - \left( {s_{0} + 1} \right)} \\{M - 1}\end{pmatrix}.}$

Equality holds only if N−(s₀+1)=0, i.e., s₀=N−1. In this case the leftside of the inequality becomes

$\begin{pmatrix}1 \\M\end{pmatrix}\quad$

i.e., only applies of M=1 However, as discussed above, M=4 due to thetwo clusters of LTE multi-cluster allocation.

Since s₀<s₁ and

${\begin{pmatrix}{N - \left( {s_{0} + 1} \right)} \\{M - 1}\end{pmatrix} \geq \begin{pmatrix}{N - s_{1}} \\{M - 1}\end{pmatrix}},$

it follows that

$\begin{pmatrix}{N - s_{0}} \\M\end{pmatrix} \geq {\begin{pmatrix}{N - s_{1}} \\{M - 1}\end{pmatrix}.}$

The equality holds only if s₁=s₀+1. Consequently, it holds that

$\begin{pmatrix}{N - s_{0}} \\M\end{pmatrix} > {\begin{pmatrix}{N - s_{1}} \\{M - 1}\end{pmatrix}.}$

The same can be applied mutatis mutandis for the other terms, so thatthe following relations are obtained:

$\begin{pmatrix}{N - s_{0}} \\M\end{pmatrix} > \begin{pmatrix}{N - s_{1}} \\{M - 1}\end{pmatrix} > \begin{pmatrix}{N - s_{2}} \\{M - 2}\end{pmatrix} > {\begin{pmatrix}{N - s_{3}} \\{M - 3}\end{pmatrix}.}$

It becomes therefore evident that

${\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle} > {\langle\begin{matrix}{N - s_{1}} \\{M - 1}\end{matrix}\rangle} > {\langle\begin{matrix}{N - s_{2}} \\{M - 2}\end{matrix}\rangle} > {\langle\begin{matrix}{N - s_{3}} \\{M - 3}\end{matrix}\rangle}$

applies, unless one of those terms equals zero. Specifically, the casethat the first term is not the largest value can only occur if:

${\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle} = 0$ $\begin{pmatrix}{N - s_{1}} \\{M - 1}\end{pmatrix} = 0$ $\begin{pmatrix}{N - s_{2}} \\{M - 2}\end{pmatrix} = 0$ $\begin{pmatrix}{N - s_{3}} \\{M - 3}\end{pmatrix} = 0$

With

${\langle\begin{matrix}x \\y\end{matrix}\rangle} = 0$

x<y and M=4, it can be concluded that:

-   -   s₀>N−4    -   s₁>N−3    -   s₂>N−2    -   s₃>N−1

With 1≤s₀<s₁<s₂<s₃≤N, it further holds that:

-   -   s₀≤N−3    -   s₁≤N−2    -   s₂≤N−1    -   s₃≤N

When combining these two constraints, the inequality holds only in thefollowing condition:

-   -   s₀=N−3    -   s₁=N−2    -   s₂=N−1    -   s₃=N

To determine the largest value of r, it is sufficient to consider thosecases where each term is non-zero. Then, in this specific case, r can beexpressed as:

$r = {\begin{pmatrix}{N - s_{0}} \\4\end{pmatrix} + \begin{pmatrix}{N - s_{1}} \\3\end{pmatrix} + \begin{pmatrix}{N - s_{2}} \\2\end{pmatrix} + {\begin{pmatrix}{N - s_{3}} \\1\end{pmatrix}.}}$

Each term becomes largest if the N−s_(n) term is as large as possible,i.e., in the following case:

$r_{\max} = {\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 2} \\3\end{pmatrix} + \begin{pmatrix}{N - 3} \\2\end{pmatrix} + \begin{pmatrix}{N - 4} \\1\end{pmatrix}}$

The following formula can further be applied:

$\begin{pmatrix}N \\4\end{pmatrix} = {\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 1} \\3\end{pmatrix}}$ $\begin{pmatrix}N \\4\end{pmatrix} = {\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 2} \\3\end{pmatrix} + \begin{pmatrix}{N - 2} \\2\end{pmatrix}}$ $\begin{pmatrix}N \\4\end{pmatrix} = {\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 2} \\3\end{pmatrix} + \begin{pmatrix}{N - 3} \\2\end{pmatrix} + \begin{pmatrix}{N - 3} \\1\end{pmatrix}}$ $\begin{pmatrix}N \\4\end{pmatrix} = {\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 2} \\3\end{pmatrix} + \begin{pmatrix}{N - 3} \\2\end{pmatrix} + \begin{pmatrix}{N - 4} \\1\end{pmatrix} + \begin{pmatrix}{N - 4} \\0\end{pmatrix}}$ $\begin{pmatrix}N \\4\end{pmatrix} = {\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 2} \\3\end{pmatrix} + \begin{pmatrix}{N - 3} \\2\end{pmatrix} + \begin{pmatrix}{N - 4} \\1\end{pmatrix} + 1}$ ${\begin{pmatrix}{N - 1} \\4\end{pmatrix} + \begin{pmatrix}{N - 2} \\3\end{pmatrix} + \begin{pmatrix}{N - 3} \\2\end{pmatrix} + \begin{pmatrix}{N - 4} \\1\end{pmatrix}} = {\begin{pmatrix}N \\4\end{pmatrix} - 1.}$

Moreover, for the maximum value of r that can result for the supportedresource allocations,

$r_{\max} = {\begin{pmatrix}N \\4\end{pmatrix} - 1}$

applies.

Furthermore, the largest values of r are obtained when

${\langle\begin{matrix}{N - s_{0}} \\M\end{matrix}\rangle}\quad$

is largest, i.e., for s₀=1.

In LTE(-A), the edge PRBs (physical resource blocks) are likely used,configured, reserved or occupied for PUCCH (physical uplink controlchannel) transmissions. Therefore, the likelihood of assigning the edgePRBs (at both sides of the spectrum) is quite low. It follows that theprobability that these edge PRBs (for example all RBGs that contain theedge PRBs) are allocated in a multi-cluster allocation is comparablylow. Furthermore, not using edge PRBs reduces the out-of-band emissionsgenerated by transmissions, so is advantageous even if those PRBs arenot used configured, reserved or occupied for PUCCH transmissions.

The largest signaled values for multi-cluster allocations occur when thestart of the first cluster is in RBG 1, i.e., in the first RBG of theuplink bandwidth. The smallest signaled values for multi-clusterallocations cannot be so easily predicted.

For example, if the uplink system bandwidth is 7 PRBs, the followingvalues apply:

N_(RB)^(UL) = 7 P = 1 N_(RBG)^(UL) = 7 N = 8 1 ≤ s₀ < s₁ < s₂ < s₃ ≤ 8$r = {{\langle\begin{matrix}{8 - s_{0}} \\4\end{matrix}\rangle} + {\langle\begin{matrix}{8 - s_{1}} \\3\end{matrix}\rangle} + {\langle\begin{matrix}{8 - s_{2}} \\2\end{matrix}\rangle} + {\langle\begin{matrix}{8 - s_{3}} \\1\end{matrix}\rangle}}$ $r_{\max} = {{\begin{pmatrix}8 \\4\end{pmatrix} - 1} = 69.}$

Consequently, for the example that the uplink system bandwidth is 7PRBs, seventy different values r exist (0 to 69). These different valuesof r are the allowed uplink resource allocations supported by thesystem. To represent seventy allowed values, 7 bits are required.

For these parameters of the exemplary system bandwidth of 7 PRBs, theequation

┌log₂(N _(RB) ^(UL)(N _(RB)^(UL)+1)/2)┐+1=┌log₂(7·8/2)┐+1=┌log₂(28)┐+1=6

provides that only 6 bits are available for the signaling of r, eventhough 7 bits would be required to cover all seventy allowed r values.The seventy allowed values and the corresponding RBG multi-clusterallocations of this example are shown in Table 3.

It can further be observed from Table 3 that the values 64-69 (shown initalics) have in common that the first RBG s₀ of the first cluster isRBG number 1, i.e., the first RBG of the system bandwidth. These statestherefore correspond to those valid states where the MSB (i.e., the bitrepresenting decimal 64) of r is set to 1. On the other hand, it can beobserved that the states that are represented by the LSB of r set to 0(shown in bold) share no similar characteristic, for example they do notshare any identical starting or ending RBG of either cluster.

TABLE 3 s₀ s₁ s₂ s₃ r 1 2 3 4 69 1 2 3 5

1 2 3 6 67 1 2 3 7

1 2 3 8 65 1 2 4 5

1 2 4 6 63 1 2 4 7 62 1 2 4 8 61 1 2 5 6 60 1 2 5 7 59 1 2 5 8 58 1 2 67 57 1 2 6 8 56 1 2 7 8 55 1 3 4 5 54 1 3 4 6 53 1 3 4 7 52 1 3 4 8 51 13 5 6 50 1 3 5 7 49 1 3 5 8 48 1 3 6 7 47 1 3 6 8 46 1 3 7 8 45 1 4 5 644 1 4 5 7 43 1 4 5 8 42 1 4 6 7 41 1 4 6 8 40 1 4 7 8 39 1 5 6 7 38 1 56 8 37 1 5 7 8 36 1 6 7 8 35 2 3 4 5 34 2 3 4 6 33 2 3 4 7 32 2 3 4 8 312 3 5 6 30 2 3 5 7 29 2 3 5 8 28 2 3 6 7 27 2 3 6 8 26 2 3 7 8 25 2 4 56 24 2 4 5 7 23 2 4 5 8 22 2 4 6 7 21 2 4 6 8 20 2 4 7 8 19 2 5 6 7 18 25 6 8 17 2 5 7 8 16 2 6 7 8 15 3 4 5 6 14 3 4 5 7 13 3 4 5 8 12 3 4 6 711 3 4 6 8 10 3 4 7 8  9 3 5 6 7  8 3 5 6 8  7 3 5 7 8  6 3 6 7 8  5 4 56 7  4 4 5 6 8  3 4 5 7 8  2 4 6 7 8  1 5 6 7 8  0

According to an embodiment of the invention, the following approach isused if insufficient bits are available to signal the whole range of ras with the above example listed in Table 3:

-   -   The bits that can be signaled represent the LSBs of r    -   Any “remaining” bits of r that cannot be signaled, i.e., the        “remaining” MSB(s) of r (if any), are set to 0.

According to another embodiment of the invention, it is further proposedthat:

-   -   The eNodeB, when determining the multi-cluster allocation,        avoids assigning multi-cluster allocations that cannot be        transmitted in the DCI. In other words, only those allocations        are determined for which the MSB(s), where applicable, are 0. In        this case, there is no need to inform the UE of the value of the        MSB(s), as it assumes them to be zero according to this        invention. Alternatively, the UE can be informed of the value of        the MSB(s), for example as part of control information signaled        to the UE.

The following advantages are obtained for these embodiments:

-   -   Multi-cluster allocations can be supported for all values of the        system bandwidth N_(RB) ^(UL), even if insufficient bits are        available to signal the unrestricted range of values of r    -   Only allocations where the first RBG of the allocation is on the        first RBG of the uplink system bandwidth cannot be realized.        However, it is expected that the first RBG is typically not        assigned due to the aspects mentioned above, so that the        relative loss to the system is comparably negligible.    -   Some allocations where the first RBG of the allocation is on the        first RBG of the uplink system bandwidth can still be realized        (for example by signaling values of r between 35 and 63):        -   In contrast, if for example the MSB was set to 1, only            allocations 64-69 could be signaled, which is a            comparatively strong restriction to the usability of            multi-cluster resource allocation.        -   In contrast, if for example the LSB was set to either 0 or            1, only 35 out of the above 70 cases of Table 3 could be            signaled, which is also putting strong restrictions on the            usability of multi-cluster resource allocation. Moreover,            these allocations do not follow a particular pattern.        -   In contrast, if only an a priori defined restricted part of            the bandwidth can be addressed by multi-cluster allocations,            it follows that for example the first RBG can never be            assigned for multi-cluster allocations. In the example of            Table 3, this would affect configurations 35-69 that would            not be usable, i.e., 50% of the cases.

According to another embodiment of the invention the same approach asoutlined above is applied, i.e., to set the non-signaled MSB bits tozero. However, in addition the interpretation of the signaled values ismodified. For example, the last RBG can be blocked from being assignableinstead of the first RBG as in the above example. This approach is amirroring of the signaled allocations and can be achieved by are-mapping of the signaled information, such as the signaled values s₀to s₃ denoting the two clusters of RBGs for LTE multi-clusterallocation. The re-mapping can be achieved according to a furtherembodiment of the invention by the following equations:

s ₀ ^(applied) =N+1−s ₃ ^(signalled)

s ₁ ^(applied) =N+1−s ₂ ^(signalled)

s ₂ ^(applied) =N+1−s ₁ ^(signalled)

s ₃ ^(applied) =N+1−s ₀ ^(signalled)

According to still another embodiment, the mirroring can be alsoobtained by defining a re-interpretation of the r values. For the aboveexample of Table 3, Table 4 shows possible relations, which are obtainedfrom the above rules for re-interpreting the values s₀ to s₃ and therule for obtaining an r-value from the values s₀ to s₃ discussed above.

TABLE 4 r^(signalled) r^(applied) 69 0 68 1 67 5 66 15 65 35 64 2 63 662 16 61 36 60 9 59 19 58 39 57 25 56 45 55 55 54 3 53 7 52 17 51 37 5010 49 20 48 40 47 26 46 46 45 56 44 12 43 22 42 42 41 28 40 48 39 58 3831 37 51 36 61 35 65 34 4 33 8 32 18 31 38 30 11 29 21 28 41 27 27 26 4725 57 24 13 23 23 22 43 21 29 20 49 19 59 18 32 17 52 16 62 15 66 14 1413 24 12 44 11 30 10 50 9 60 8 33 7 53 6 63 5 67 4 34 3 54 2 64 1 68 069

This embodiment is particularly advantageous if for example the last RBGconsists of fewer PRBs than the first RBG. For example, assuming thatN_(RB) ^(UL)=85, then the exemplary reinterpretation illustrated inTable 4 definition and a RBG size of P=4 (i.e., the RBG has 4 PRBs) onecan determine that N_(RBG) ^(UL)=22. Preferably, N_(RBG) ^(UL)−1=21 RBGsare each set to a size of P=4 and the remaining 22^(nd) RBG is composedof only of 1 PRB. Generally, it is possible that either all RBGs will beof the same size P (if N_(RB) ^(UL) is an integer multiple of P), orN_(RBG) ^(UL)−1 will be of size P and one “irregular” RBG will be ofsize in the range {1, 2, . . . ,P−1}. This occurs usually if N_(RB)^(UL) is not an integer multiple of P.

It can be noted that the loss for the system is minimum if the“irregular” RBG cannot be assigned by multiple-cluster allocations.However, this loss applies to multi-cluster allocation only and the PRBsof the “irregular” RBG can still be assigned by single-clusterallocations, or by multi-cluster allocations that do not employ thisre-interpretation, e.g., by other UEs.

Preferably, the “irregular” RBG is either the first or the last RBG. Ifit is the first RBG, the approach without re-interpretation isbeneficial, while in the other case, the approach including there-interpretation of the signaled value can be advantageously applied.

According to still another embodiment, the re-interpretation step can beapplied by adding an offset to the signaled r-value, i.e., applyingr^(applied)=r^(signalled)+r^(offset). For example,r^(offset)=r^(max)−r_(max) ^(signalled) with r_(max) ^(signalled) as themaximum value that can be signaled with the available bits.Alternatively, r_(max) ^(signalled) can be configured by the eNodeBand/or signaled to the UE. The advantage of is the simplicity of animplementation.

As a simple (from implementation perspective) but not as effectivealternative approach, the re-interpretation can consist of subtractingthe signaled value from the maximum valuer_(applied)=r_(max)−r^(signalled), i.e., in the above example to user_(applied)=69−r_(signalled).

According to another embodiment of the invention, the re-interpretationto be applied could also be configured or signaled from the eNodeB. Withsuch signaling, the flexibility of the possible assignments by eNodeB isincreased, at the cost of more complex implementation at the UE side andpossibly also at the transmitter side. In another aspect of thisembodiment the re-interpretation behavior is configured by the basestation for each UE individually and is signaled to same, e.g., usinghigher layer signaling such as RRC or MAC signaling in the context ofLTE or LTE-A. For example, a first UE is configured withoutre-interpretation, while a second UE is configured withre-interpretation. Then, the first RBG can be allocated to the second UEand the last RBG can be allocated to the first UE in the same subframeusing multi-cluster allocations each, so that all RBGs in the system canactually be utilized simultaneously from a system perspective.

In regard to the embodiments of the invention concerning the proposedre-interpretation aspects, DCI format 0 or DCI format 4 of 3GPP LTE(-A),for example Release 10, may be used. Both DCI formats concernmulti-cluster allocation as discussed above.

FIG. 7 shows an exemplary method for receiving and determining resourceallocation information at a terminal of a mobile communication system asit can be used in regard to the discussed embodiments of the presentinvention.

The exemplary method of FIG. 7 can be performed by a terminal, such as aUE or a relay node in an LTE or UMTS system. The terminal receivescontrol information that indicates allocated resources, such asallocated RBs or RBGs for uplink or downlink transmissions of theterminal. The allocated resources can be received as part of a DCI, asillustrated by step 701.

The terminal will then extract the bits of the signaled resourceallocation information from the received control information, as shownby step 703. In case of LTE, the DCI includes dedicated fields and/orflags for indicating at least the allocated resources (i.e., RBs orRBGs), as discussed above. Typically, the received resource allocationinformation represents one or more bit-values that indicate theallocated resources to the terminal as discussed above.

The terminal determines in step 705 the allocated resource informationfrom the received and extracted bits. As discussed above, steps 703 and705 can be one and the same step, if the signaled information (e.g., thesignaled bits in the resource allocation field of the DCI) specifiesdirectly the allocated resource, as in prior systems discussed in thebackground section. According to embodiments of the invention, therecould be insufficient bits available for signaling all allowedcombinations of the allocated resources, in which case, the signaledbits received by the terminal do not directly indicate the allocatedresource as discussed above. For some embodiments of the invention,non-signaled bits are set to a predefined value. In this case, theterminal can set these non-signaled bits according to the predefinedscheme (that can be fixed at the terminal or signaled to the UE) as partof step 705 to result at the actual resource allocation information.Alternatively, the terminal is configured to interpret the received bitsaccording to the predefined scheme to identify actual allocated resourcewithout actively setting the non-signaled bits to a given value. Indifferent embodiments of the invention, the signaled number of bits issufficient to represent the allowed resource allocation and the steps703 and 705 can be one step.

As an optional step 707, the terminal can apply a re-interpretation orre-mapping of the signaled and received resource allocations can beapplied according to the discussed re-interpretation embodiments of theinvention. As also discussed, the re-interpretation can be also signaledto the terminal, in which case an additional step of receiving andextracting an re-interpretation flag can be performed, either separatelyto or as part of steps 703 and 705.

FIG. 7A shows exemplary steps that can be performed as part of thedetermining step 705 of FIG. 7 according to another embodiment of thepresent invention. As noted above, the terminal can determine the formatand size of the received DCI, including the number (and location) of thebits used for signaling resource allocations. The number of signaledbits is also referred to as the “number of available bits” in the abovedescription of the different aspects of the present invention. As it isalso discussed above, the terminal is further able to determine thenumber of bits that is required to address or signal all allowedresource allocations that are supported by the communication system. Assuch, the terminal can determine whether the signaled bits (i.e., thenumber of bits in the received DCI that are extracted in step 703 ofFIG. 7) is sufficient to represent all allowed resource allocations thatare supported by the communication system, as illustrated in step 710 ofFIG. 7A.

If the number of signaled bits is sufficient, the extracted bits of step703 of FIG. 7 are determined to be the resource allocation information,as shown in step 712 of FIG. 7A.

If the number of signaled bits is insufficient, the extracted bits ofstep 703 of FIG. 7 are only one part of the resource allocationinformation. In this case, as shown by step 714, the predetermined oneor more bits that are not signaled to the terminal (also referred to asthe “remaining bit(s)” in the above description of the different aspectsof the present invention) are then added to the signaled bits asextracted bits in step 703 of FIG. 7. As discussed above, the positionand the value of the non-signaled bits that are to be added arepredetermined. The result of combining the extracted bits and thepredetermined non-signaled bits as illustrated in step 714 is then usedas the resource allocation information. Thereafter, there-interpretation step 707 of FIG. 7 can be performed using the resultof either step 712 or step 714.

FIG. 8 shows an exemplary method for determining and transmittingresource allocation information by a base station of a mobilecommunication system as it can be used in regard to the discussedembodiments of the present invention.

The exemplary method of FIG. 8 can be performed a base station, such asan eNodeB/NodeB or a relay node in an LTE or UMTS system. The basestation determines the assigned resources allocation for a terminal,such as allocated RBs or RBGs for uplink or downlink transmissions ofthe terminal, as illustrated by step 801.

According to step 803, the base station determines whether the number ofavailable bits is sufficient for representing the allowed resourceallocations supported by the system as discussed above for severalembodiments of the invention.

If the number of available bits is sufficient, the base station cancreate the DCI in the common manner as illustrated by step 807.

If the number of available bits is insufficient, the base station canset one or more predetermined bits of the resource allocationinformation (i.e., the resource allocation information that would haveto be signaled to address all allowed resource allocations supported bythe system) to a predetermined value, as illustrated by step 809 anddiscussed above for several embodiments of the invention.

According to step 811, the base station creates the DCI with those bitsto be signaled according to the respective embodiments of the invention.

Steps 803, 805 and 809 can be performed once by the base station or onlyunder given circumstances, but not for each control informationsignaling step. The result can then be applied in multiple subsequentsignaling steps and for creating and transmitting several DCIs toterminal(s) serviced by the base station. Alternatively, the numbers ofbits and values determined can be predefined or fixed, in which casesteps 803, 805 and 809 do not have to be performed by the base station.Moreover, some embodiments of the invention concern the case where thereare sufficient bits available, such as the embodiments of the inventionconcerning the re-interpretation aspect that can be implemented with andwithout sufficient bits as discussed above. For these embodiments of thesteps 803, 805 and 809 may not be performed by the base station.

Once the DCI is created, the base station can transmit the DCI to theterminal as illustrated in step 813.

The exemplary methods shown in FIGS. 7 and 8 can concern the samecommunication system in that the DCI received by the terminal in step701 was transmitted by the base station in step 813.

Instead of setting the MSB(s) of the resource allocation information(e.g., the allocated RBGs) to 0 as discussed above, the bit(s) that areset and/or the value to which they are set can be configured by theeNodeB.

Whether a re-interpretation is applied or not can also be configured bythe eNodeB, preferably per UE. According to another embodiment, thestatus whether re-interpretation is applied is signaled in the controlinformation that carries the resource allocation. This could be achievedby a single bit (on/off). If this bit is taken from the LTE DCI resourceallocation field according to the above example of Table 3, oneadditional MSB is set to zero. This means that with the earlier outlinedexample, instead of 6 available bits, 1 bit is used as are-interpretation flag (on/off), while the remaining 5 bits denote theLSBs of r. Accordingly, the resources that can be assigned to an UE arelimited to the values 0-31 of the Table 3. If the re-interpretation bitis set to “off”, this means that states 0-31 from the table can beallocated. If the re-interpretation flag is “on”, this means that states0-31 can be signaled and a re-interpretation scheme is applied.According to another embodiment of the invention, the re-interpretationbit set to a first value means that a first set of states can beallocated by the available bits, and the re-interpretation bit set to asecond value means that a second set of states can be allocated by theavailable bits. The first and second set of states can be configured andsignaled by the base station.

As it has been discussed above, embodiments of the present inventionallows to define (preferably per UE) which RBs or RBGs or combinationsthereof can actually be addressed with the available number of bits ifthe signaling is insufficient to assign all allowed RB or RBGcombinations in the multi-cluster approach.

However, according to yet another embodiment of the invention, thenumber of RBGs (e.g., for multi-cluster allocation) or the number of RBs(e.g., for single-cluster allocation) that can be addressed by anavailable number of bits can be determined and set by the system or thebase station. For example, the number of addressable RBGs can bedetermined by:

$N_{RBG}^{addressable} = {\left\lfloor {\frac{3}{2} + \sqrt{\frac{5}{4} + \sqrt{1 + {24 \cdot 2^{N_{{bits},\; {available}}}}}}} \right\rfloor - 1}$

Thus, the signaled bits can be interpreted to define a multi-clusterallocation in the range from RBG 1 to RBG N_(RBG) ^(addressable). Then,another parameter can be configurable which defines whether are-interpretation is applied similar to the solutions outlinedpreviously. Those skilled in the art will recognize that the givenformula can also be applied to determine the number of addressable RBsby substituting N_(RBG) ^(addressable) by N_(RB) ^(addressable).

It is to be noted that this embodiment of the invention can be used tolimit the assignable resource allocations for a UE, even if theavailable number of signaling bits would be sufficient to address allallowed resource allocations.

In addition, a re-interpretation can be defined such that the RB or RBGindices within the N_(RB) ^(UL) RBs are first configured. In case RBsare defined, those RBs are formed to RBGs, where generally non-adjacentRBs may be located in one RBG. The multi-cluster allocation signal isthen used to assign RBGs from within this restricted set of RBGs. Thereis a choice whether the RBG size P is determined from the value N_(RB)^(UL) or N_(RBG) ^(addressable). The first has the advantage that theRBG size is identical for all UEs under the eNodeB, which simplifies thescheduling algorithm due to only the single RBG size which has to betaken into account. On the other hand, with the second way thegranularity of the addressable RBGs is improved, particularly if a veryrestricted subset of RBs is defined for possible multi-clusterallocations. For example, in a system with N_(RB) ^(UL)=50 PRBs, thenormal RBG size is P=3. The network could desire or decide to use only16 out of those 50 PRBs (which for example corresponds to a frequencyreuse factor of roughly ⅓ that is quite common in cellular communicationsystems). This means for the above mentioned first way that 6 RBGs, eachof size 3 PRBs, are selected for multi-cluster allocation. For the abovementioned second way, there would be 8 RBGs of size 2 available formulti-cluster allocation, since for a system of 16 PRBs the RBG size is2. Thus, the granularity and scheduling flexibility is increased. It canbe noted that with the second way, it is possible that again more bitsare required than available. However, in such a case, the presentinvention has proposed a solution to signal the allocations.

Since the number of bits required for multi-cluster allocations dependson N_(RB) ^(UL) as well as on the RBG size P (which is itself a functionof N_(RB) ^(UL)), it is also possible to modify the definition of theRBG size P so that the number of available bits is sufficient to holdthe multi-cluster allocation for the resulting number of RBGs.

From the available number of bits for the multi-cluster allocation, thenumber of addressable RBGs can be determined by

$N_{RBG}^{addressable} = {\left\lfloor {\frac{3}{2} + \sqrt{\frac{5}{4} + \sqrt{1 + {24 \cdot 2^{N_{{bits},\; {available}}}}}}} \right\rfloor - 1.}$

Therefore, the RBG size is determined from the number of uplink resourceblocks and the number of addressable RBGs is determined by:

P _(RBG) ^(UL) =┌N _(RB) ^(UL) /N _(RBG) ^(addressable)┐.

According to still another of the invention, it is therefore suggestedto determining the RBG size for a given number of uplink resource blocksof a 3GPP LTE or 3GPP LTE-A communication system by Table 5 (derivedusing the above formula) instead of the suggested Table 2 of the 3GPPLTE specification discussed in the background section.

TABLE 5 N_(RB) ^(UL) P_(RBG) ^(UL) ≤6, 8     1  7, 9-26 2 27-54 3 55-84,91-100  4 85-90, 101-110 5

It can be seen that Table 5 determines the smallest possible RBG sizeP_(RBG) ^(UL) for which the number of bits is sufficient. Therefore,Table 5 provides the finest scheduler granularity and consequently themost effective allocation possibility in the scheduler (e.g., the NodeB)for all numbers of uplink resource blocks. However, from animplementation perspective it can be beneficial if the RBG size is anon-decreasing function of the number of uplink resource blocks. Fromthat perspective, once the RBG size is a first value for a certainnumber of resource blocks, the RBG size should not be smaller than thatfirst value for any larger number of resource blocks. Consequently, totake this into account, the Table 5 can be modified to resemble Table 6:

TABLE 6 N_(RB) ^(UL) P_(RBG) ^(UL) ≤6 1 7-26 2 27-54  3 55-84  4 85-1105

Another aspect of the invention relates to the implementation of thedescribed various embodiments using hardware and/or software. A skilledperson will appreciate that the various embodiments of the invention canbe implemented or performed using computing devices or one or moreprocessors. A computing device or processor may for example be a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic devices, etc. The various embodimentsof the invention may also be performed or embodied by a combination ofthese devices.

Further embodiments of the invention concern a terminal configured oradapted to perform the terminal-side steps of the different methods andfunctionalities of the above discussed embodiments.

Still further embodiments of the invention concern a base stationconfigured or adapted to perform the base station-side steps of thedifferent methods and functionalities of the above discussedembodiments.

Further, the various embodiments of the invention may also beimplemented by means of software modules or computer-readableinstructions stored on one or more computer-readable media, which whenexecuted by a processor or device component, perform the describedvarious embodiments of the invention. Likewise, any combination ofsoftware modules, computer-readable media and hardware components isanticipated by the invention. The software modules may be stored on anykind of computer readable storage media, for example RAM, EPROM, EEPROM,flash memory, registers, hard disks, CD-ROM, DVD, etc.

A person skilled in the art will appreciated that numerous variationsand/or modifications may be made to the present invention as disclosedby the specific embodiments without departing from the spirit or scopeof the invention as defined in the appended claims. The discussedembodiments are, therefore, to be considered in all respects to beillustrative and not restrictive.

1. A terminal apparatus comprising: a receiver which, in operation,receives downlink control information which includes a resourceallocation field; and circuitry which is coupled to the receiver andwhich, in operation, determines resources assigned to the terminalapparatus based at least on available bits in the resource allocationfield; wherein when a plurality of clusters are allocated to theterminal apparatus and a number of the available bits is smaller than anumber of bits necessary to indicate the allocated plurality ofclusters, the circuitry assumes a portion of the bits necessary toindicate the allocated plurality of clusters unrepresented by theavailable bits to be of a defined value.
 2. The terminal apparatusaccording to claim 1, wherein the available bits include LSBs (LeastSignificant Bits) of the bits necessary to indicate the allocatedplurality of clusters.
 3. The terminal apparatus according to claim 2,wherein the portion unrepresented by the available bits includes MSBs(Most Significant Bits) of the bits necessary to indicate the allocatedplurality of clusters.
 4. The terminal apparatus according to claim 1,wherein the defined value is zero.
 5. The terminal apparatus accordingto claim 1, wherein the plurality of clusters are a plurality ofresources which are discontinuous on a frequency axis, each clusterincluding a plurality of resource blocks (RBs) which are continuous onthe frequency axis.
 6. The terminal apparatus according to claim 1,wherein the resource allocation field includes a hopping flag, whichindicates whether frequency hopping is applied when a single cluster isallocated.
 7. The terminal apparatus according to claim 1, wherein thenumber of the available bits is determined based on a system bandwidth.8. The terminal apparatus according to claim 1, wherein the circuitry,in operation, prepares uplink data to be transmitted on uplink resourcesdetermined based at least on the available bits in the resourceallocation field.
 9. A communication method implemented by a terminalapparatus, the communication method comprising: receiving downlinkcontrol information which includes a resource allocation field;determining resources assigned to the terminal apparatus based at leaston available bits in the resource allocation field; and in response to anumber of the available bits being smaller than a number of bitsnecessary to indicate a plurality of clusters allocated to the terminalapparatus, assuming a portion of the bits necessary to indicate theallocated plurality of clusters unrepresented by the available bits tobe of a defined value.
 10. The communication method according to claim9, wherein the available bits include LSBs (Least Significant Bits) ofthe bits necessary to indicate the allocated plurality of clusters. 11.The communication method according to claim 10, wherein the portionunrepresented by the available bits includes MSBs (Most SignificantBits) of the bits necessary to indicate the allocated plurality ofclusters.
 12. The communication method according to claim 9, wherein thedefined value is zero.
 13. The communication method according to claim9, wherein the plurality of clusters are a plurality of resources whichare discontinuous on a frequency axis, each cluster including aplurality of resource blocks (RBs) which are continuous on the frequencyaxis.
 14. The communication method according to claim 9, wherein theresource allocation field includes a hopping flag, which indicateswhether frequency hopping is applied when a single cluster is allocated.15. The communication method according to claim 9, wherein the number ofthe available bits is determined based on a system bandwidth.
 16. Thecommunication method according to claim 9, comprising: preparing uplinkdata to be transmitted on uplink resources determined based at least onthe available bits in the resource allocation field.